A voltage regulator is generally used in an electronic system to ensure that power supply supplies power stably in the electronic system and an output voltage of the power supply may be regulated. FIG. 1 illustrates a basic structure of a conventional voltage regulator. In FIG. 1, the voltage regulator includes an operational amplifier, a regulation transistor, a voltage dividing resistor R1 and a voltage dividing resistor R2. VIN is an input voltage of the voltage regulator, VOUT is an output voltage of the voltage regulator, and VREF is a reference voltage generated by a bandgap reference generation circuit. An operating process of the voltage regulator may be briefly summarized as follows: a reference voltage VREF is input to an inverting input terminal of the operational amplifier, and an output voltage VOUT subjected to sampling by the voltage dividing resistors R1 and R2 is input to a non-inverting input terminal, and the output voltage VOUT of the operational amplifier is connected to the regulation transistor (that is, the pass transistor in FIG. 1). The regulation transistor is configured to stabilize the output voltage VOUT to achieve stable power supply. In addition, the output voltage VOUT is then regulated by regulating a ratio of the voltage dividing resistor R1 to the voltage dividing resistor R2.
When the electronic system is in a standby state, the voltage regulator still needs to supply the output voltage VOUT to ensure normal operation of a part of modules in the electronic system. However, when the electronic system is in the standby state, a load current output by the voltage regulator is small, whereas the voltage regulator may have high power consumption due to presence of the voltage dividing resistors R1 and R2.